[Epidemiology of hepatocellular carcinoma]

Hepatocellular carcinoma (HCC), which constitutes the majority of primary liver cancer, is endemic to certain areas of the world. The incidence rate varies considerably from area to area, and the difference between Mozambique, South Africa, and northern Europe in the age group of 25 to 34 years is more than 500-fold in males. It now seems that the area along the Yangtse River to the north of Shanghai, China, has an incidence rate just as high as Mozambique. Such differences are due to the predominant etiologic factors such as aflatoxin B1, and hepatitis B and C virus infections. While the hepatitis B infection rate is decreasing among HCC patients, hepatitis C infection has been increasing in the population and in HCC patients in some countries, such as Japan, Italy and Spain. Regardless of the area, males are more prone to HCC than females, and this ratio is also changing with time in some countries because of the change in the relative proportion of hepatitis B and C among patients. The known etiologic factors, such as hepatitis B, hepatitis C, Budd-Chiari syndrome and chemical carcinogens, are briefly reviewed.